Ocean Wave Height

[kko]

When planning ocean voyages, we sought information about the maximum wave heights occurring in specific areas during certain months of the year. Particularly, when preparing to cross the Atlantic during the summer months, we were interested in the maximum reach of dangerous waves generated by hurricanes. By using public GRIB database and our own R language scripts, we have generated graphics which many sailors find interesting. Therefore, we would like to share these with all the community. In the link, there are graphics along the script source code, so you can modify it to plot any data from the GRIB database you want. Hope you find it helpful.


Ocean Wave Height | Stubborn Sailors

 

[Laser310]

When planning ocean voyages, we sought information about the maximum wave heights occurring in specific areas during certain months of the year. Particularly, when preparing to cross the Atlantic during the summer months, we were interested in the maximum reach of dangerous waves generated by hurricanes. By using public GRIB database and our own R language scripts, we have generated graphics which many sailors find interesting. Therefore, we would like to share these with all the community. In the link, there are graphics along the script source code, so you can modify it to plot any data from the GRIB database you want. Hope you find it helpful.


Ocean Wave Height | Stubborn Sailors

cool.

It's interesting that tropical storm tracks stand out - i would have expected that the high waves would be more diffuse.

I think larger images would be useful - maybe even some that are restricted to areas likely to be of interest; the north atlantic, for example.

another thing, if you felt like doing more work..., how about if as i mouse over the image, i see a window that displays the distribution of wave heights for that location in that month?

I went to grad school with the guy responsible for wgrib...

 

[Laser310]

Are you familiar with the COGOW site?

Climatology of Global Ocean Winds

 

[kko]

Nice you like it Maybe someday we will rework it further. In the script itself you can easily plot zoom on any given area by redefining coordinates. Needs basic R language knowledge, but not "expert level".

 

[kko]

Are you familiar with the COGOW site?

Climatology of Global Ocean Winds

Didn't know that. Thanks.

 

[Laser310]

Nice you like it Maybe someday we will rework it further. In the script itself you can easily plot zoom on any given area by redefining coordinates. Needs basic R language knowledge, but not "expert level".

your R scripts are not part of that download - are they?

 

[kko]

your R scripts are not part of that download - are they?

They are in the zip file, together with the wgrib library, so you have all what we have used to create the plots. Our scripts are: downloader.R and gribWavePlot.R. You need R Studio to use it.

 

[Laser310]

They are in the zip file, together with the wgrib library, so you have all what we have used to create the plots. Our scripts are: downloader.R and gribWavePlot.R. You need R Studio to use it.

thanks

i didn't see the at first

 

[kko]

thanks

i didn't see the at first

You need some manual work to use these, i.e. download particular month, rename the file and put it in appropriate path and set appropriate data length (to match downloaded time period). This was intended for our own purposes, not "user friendly". But still more and more people asked us to share the sources to plot some other interesting GRIB data, so we decided to just give it to everybody. Feel free to improve the files and re-share if you want.

 

[mjcp]

Nice.

Assume the heights are in meters? For tidiness, perhaps edit the test "Legend" to "Legend (m)" ?

M

 

[LittleSister]

I am not sure wave/swell height alone tells one much.

I have been out on the ocean (in a gale, even) and also in the western English Channel (in F3-F4) with huge swells which were not at all a problem, while much smaller waves (e.g. in more confined waters) have been dangerous and seriously difficult and uncomfortable.

I believe the combination of wave/swell height with wave frequency/wavelength gives a much more meaningful indication of conditions and hazard.

 

[Laser310]

I am not sure wave/swell height alone tells one much.

there are measures of "roughness" that one might compute from the era5 data and present in a similar fashion.

a simple one is wave steepness, defined as wave height divided by wavelength

there are others.

it's maybe worth noting that in era5, wave data is at 0.5deg resolution, compared with 0.25deg for most atmospheric data

 

[kko]

I am not sure wave/swell height alone tells one much.

I have been out on the ocean (in a gale, even) and also in the western English Channel (in F3-F4) with huge swells which were not at all a problem, while much smaller waves (e.g. in more confined waters) have been dangerous and seriously difficult and uncomfortable.

I believe the combination of wave/swell height with wave frequency/wavelength gives a much more meaningful indication of conditions and hazard.

Sure. Probably you can plot this also from the Copernicus database. For our summer Atlantic crossing we were interested in the maximum reach of waves generated by hurricanes. These are obviously coming from all directions, breaking and dangerous. But it is true what you say. E.g., on some passages, every 6 hours wave changed from smooth to choppy only because of the current direction.

 

[kko]

there are measures of "roughness" that one might compute from the era5 data and present in a similar fashion.

a simple one is wave steepness, defined as wave height divided by wavelength

there are others.

it's maybe worth noting that in era5, wave data is at 0.5deg resolution, compared with 0.25deg for most atmospheric data

Can be interesting before our next plan, which is Pacific ocean. Indeed "roughness" matters...